“What do you think is the worst that could happen by issuing a "0 +" on an integer value that is meant to be used as a valid pointer in the first place?”
Remember: &(((int32_t *)0) + 5) == 20. From: openocd-development-boun...@lists.berlios.de [mailto:openocd-development-boun...@lists.berlios.de] On Behalf Of Redirect "Slash" NIL Sent: Saturday, October 17, 2009 6:14 PM To: openocd-development@lists.berlios.de Subject: Re: [Openocd-development] [PATCH] cast from long to HANDLER on MinGW-W64 2009/10/17 David Brownell <davi...@pacbell.net<mailto:davi...@pacbell.net>> What's with the strange "(HANDLE)(0 + _get_osfhandle())"? The "0 +" is mutant... Yeah. The problem here is that HANDLE is typedef'd as void* (in winnt.h), whereas _get_osfhandle() returns a long (http://msdn.microsoft.com/en-us/library/ks2530z6.aspx), and gcc insists on returning a warning when casting a 32 bit long into a 64 bit pointer ("cast to pointer from integer of different size"). The most elegant way I found to avoid that warning is to do an arithmetic operation first. Of course one has to wonder why a function that is meant to return a handle does not actually return a type HANDLE... The only other way I see to do it is to add idefs for MINGW64 so that we cast _get_osfhandle() to a long long first. What do you think is the worst that could happen by issuing a "0 +" on an integer value that is meant to be used as a valid pointer in the first place? _get_osfhandle is meant to provide a pointer (handle) that is valid for the OS it's actually being executed in. It's just that for whatever reason, the makers of that function decided to return anything but a handle but I still think what we're doing here should be pretty safe. Regards
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